IELs are known to be important for regulating intestinal barrier function, considering their close association with intestinal epithelial cells. The specific microenvironment of intestine determines the unique cellular and molecular features of IELs which potentially impact IELs function. We found that CD101 is highly expressed on IELs. We also found the loss of CD101 causes disrupted intestinal barrier and elevated bacterial invasion, leading to increased risk of intestinal inflammation. We are interested in studying molecular mechanisms of how CD101 controls IELs function to regulate intestinal barrier function.